1. Field of the Invention
The present invention relates to compositions for dyeing or tinting hair. In particular, the present invention relates to compositions for progressively dyeing hair.
2. Brief Description of the Background Art
The art of dyeing or tinting hair and compositions for the same are generally well known. Although selecting a composition which will dye or tint (hereinafter collectively referred to as "color") hair without unexpected and undesirable results involves a significant amount of experience, the application of modern coloring compositions itself is usually relatively straightforward. In fact, modern colorants are often applied by the individual at home, rather than by a professional.
It will be understood that, for a variety of reasons, many individuals who color their hair do not want that fact to be obvious to others. Therefore, individuals typically select natural colors for their hair, which are often colors close to those that their hair displayed previously. Although such choices minimize the likelihood that others will notice that an individual's hair has been colored, the new color will nevertheless be apparent to close or frequent acquaintances of the individual. This may prove to be embarrassing, for instance, if the individual is self-conscious about having colored hair.
This problem has been previously addressed by utilizing coloring compositions which progressively color hair over a relatively extended period of time (hereinafter referred to as "progressive colorants"). Although multiple successive applications of progressive colorants provide a definite darkening of hair color, progressive colorants are thus characterized by an absence of immediate drastic change in hair color resulting from a single application.
Progressive colorant compositions have utilized metallic dyes, such as lead, silver, nickel, cobalt, copper, bismuth and the like to deposit colored metal salts on the hair. Lead is most commonly employed today in commercial compositions in the form of lead acetate. The lead acetate is present with precipitated sulfur in an aqueous carrier and, when applied to hair, slowly reacts with the sulfur and the sulfur in the hair keratin so as to gradually deposit salts of lead, such as lead sulfide and lead oxide, on the hair cuticle and within the hair shaft.
Although the lead acetate-precipitated sulfur coloring product is now widely used commercially for hair coloring, it has some characteristics that may not be entirely satisfactory to all potential users.
For example, this known commercial product is a cloudy liquid and therefore may give the impression of heaviness or viscousness which on the hair may be perceived to impair the natural appearance of the hair.
Further, if allowed to sit on a shelf for a period of time, this commercial product may show packed precipitated sulfur particles and therefore may require extensive shaking to properly distribute the elemental sulfur for most effective coloring. This characteristic may cause the product to be perceived as "chemical" in nature.
This known commercial product also tends to produce brown hair color. Therefore, potential users whose natural hair color is blonde or light brown may not be entirely happy with the resulting shade.
The known commercial product often requires five to seven days to produce the desired hair color and, in order to achieve that color, shampooing should occur less frequently. Therefore, potential users who ordinarily wish to shampoo more frequently may find this characteristic not to their liking.
Finally, this known commercial product, when in place on the hair, sometimes produces a light sulfur odor that a small percentage of users may notice and find objectionable.
It would, therefore, be advantageous to produce a progressive hair colorant composition with improved characteristics, which could be applied by an individual at home, that a large number of potential users will find very satisfactory.